Question

Silane is a gas that is used to prepare extremely pure silicon for use in semiconductors, such as computer chips. A sample of silane has a mass of 15.0 g and occupies a volume of 4.81 L at a pressure of 2.35 atm and a temperature of 22 ºC. What is the molar mass of silane?

Answer 1

Answer:

Molar mass of silane = 32.15 g/mol

Explanation:

Given:  

Pressure = 2.35 atm

Temperature = 22 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T₁ = (22 + 273.15) K = 295.15 K  

Volume = 42.9 L

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

2.35 atm × 4.81 L = n × 0.0821 L.atm/K.mol × 295.15 K  

⇒n = 0.4665 moles

Given, Mass = 15.0 g

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.4665\ mole= \frac{15.0\ g}{Molar\ mass}$

Molar mass of silane = 32.15 g/mol